The assignee of the present application, The Boeing Company, is a leading innovator in the design of high performance, low cost, compact phased array antenna modules. The Boeing antenna module shown in FIGS. 1a-1c have been used in many military and commercial phased array antennas from X-band to Q-band. These modules are described in U.S. Pat. No. 5,866,671 to Riemer et al and U.S. Pat. No. 5,276,455 to Fitzsimmons et al, both being hereby incorporated by reference.
The assignee of the present application, The Boeing Company, is a leading innovator in the design of high performance, low cost, compact phased array antenna modules. The Boeing antenna module shown in FIGS. 1a-1c have been used in many military and commercial phased array antennas from X-band to Q-band. These modules are described in U.S. Pat. No. 5,886,671 to Riemer et al and U.S. Pat. No. 5,276,455 to Fitzsimmons et al.
The in-line first generation module was used in a brick-style phased-array architecture at K-band and Q-band. This approach is shown in FIG. 1a. This approach requires some complexity for DC power, logic and RF distribution but it provides ample room for electronics. As Boeing phased array antenna module technology has matured, many efforts made in the development of module technology resulted in reduced parts count, reduced complexity and reduced cost of several key components of such modules. Boeing has also enhanced the performance of the phased array antenna with multiple beams, wider instantaneous bandwidths and polarization flexibility.
The second generation module, shown in FIG. 1b, represented a significant improvement over the in-line module of FIG. 1a in terms of performance, complexity and cost. It is sometimes referred to as the xe2x80x9ccan and springxe2x80x9d design. This design can provide dual orthogonal polarization in an even more compact, lower-profile package than the inline module of FIG. 1a. The can-and-spring module forms the basis for several dual simultaneous beam phased arrays used in tile-type antenna architectures from X-band to K-band. The can and spring module was later improved even further through the use of chemical etching, metal forming and injection molding technology. The third generation module developed by the assignee, shown in FIG. 1c, provides an even lower-cost production design adapted for use in a dual polarization receive phased array antenna.
Each of the phased-array antenna module architectures shown in FIGS. 1a-1c require multiple module components and interconnects. In each module, a relatively large plurality of vertical interconnects such as buttons and springs are used to provide DC and RF connectivity between the distribution printed wiring board (PWB), ceramic chip carrier and antenna probes. Accordingly, there remains a need to even further reduce the cost of a phased array antenna module by reducing parts count, the number of manufacturing steps needed for producing the module, and assembly complexity of the module.
The present invention is directed to an integrated ceramic chip carrier module for a phased array antenna. The module combines the antenna probe (or probes) of the phased array module with the ceramic chip carrier that contains the module electronics into a single integrated ceramic component. The resulting integrated ceramic chip carrier module has fewer independent components, higher performance, improved dimensional precision and increased reliability. The module of the present invention also allows a phased array antenna to be manufactured at a lower overall cost than with previous antenna module designs.
In one preferred embodiment the module of the present invention comprises a plurality of distinct, low temperature ceramic layers which are co-fired using well known ceramic manufacturing technology to form a single module. In one preferred embodiment these layers comprise an I/O (input/output) layer, a wave guide layer and an RF probe layer. Subsequent to forming the module, a seal ring and a lid are preferably secured to the I/O layer to provide a hermetically sealed compartment for enclosing the integrated circuit chips carried on the I/O layer.
It is a principal advantage of the module of the present invention that the module requires no button holder, and no buttons or springs to facilitate the vertical DC and RF interconnects/connector between the layers of the module. The interconnects embodied in the present invention are provided by vias formed in each of the layers and filled with a suitable electrically conductive material during manufacturing of the module. This eliminates the concern over assembly/alignment tolerances that exist with conventional vertical interconnects such as buttons and springs which are needed to make the electrical connections between various layers and/or components of traditional modules. The module of the present invention further avoids the use of chemical etching/metal forming and injection molding of the antenna probes, which are all required with previous module designs.
The module of the present invention thus eliminates vertical interconnects between the ceramic chip carrier and antenna probes and takes advantage of the fine line accuracy and repeatability of multi-layer, co-fired ceramic technology. This metallization accuracy, multi-layer registration produces an even higher performance, even more stable antenna module. The integrated module of the present invention further provides enhanced flexibility, layout and signal routing through the availability of stacked, blind and buried vias between internal layers, with no fundamental limit to the layer count in the ceramic stack-up of the module.